Female quick coupling fitting element for pipes

ABSTRACT

A female element ( 1 ) is described comprising a hollow internal body ( 2 ) having an end ( 3 ) provided with fastening means ( 5 ) to one of the pipes to be joined, a hollow external body ( 7 ) coaxial with said internal body ( 2 ) and having an end ( 8 ) which axially protrudes with respect to another end ( 4 ) of the internal body ( 2 ) opposite to that provided with fastening means ( 5 ), one rigid central stem ( 9 ) coaxially supported by said internal body ( 2 ) by means of a transversal perforated base ( 18 ) and having a widened end ( 10 ) near said protruding end ( 8 ) of the external body ( 7 ), an axially sliding sealing bush ( 12 ) coaxially arranged about said stem ( 9 ) and elastically stressed to be engaged with said widened end ( 10 ) of the stem ( 9 ) to prevent the passage of fluid within the female element ( 1 ), a cleaning bush ( 14 ) coaxially arranged about the sealing bush ( 12 ) and axially stressed in position so as to prevent the entrance of dirt about the sealing bush ( 12 ) and a lock sleeve ( 16 ) arranged about the protruding end ( 8 ) of the external body ( 7 ) and engageable with a complementary end of a male element to ensure the stable union of the two male and female elements of the fitting. The stem ( 9 ) is fixed to said base ( 18 ) by means of at least one half bush ( 25 ) radially fitted and axially locked in corresponding seats ( 26, 27 ) of said stem ( 9 ) and said base ( 18 ) (FIG.  1 ).

The present invention relates to a female quick coupling fitting element for pipes.

For the transmission of fluids, fittings which may be rapidly reciprocally coupled to connect rigid or flexible pipes, in turn connected to a fluid feed or user, must frequently be used.

The known quick coupling fittings usually consist of two elements, called male and female, which are fastened to respective pipes to be joined and which can be reciprocally coupled by screwing or snapping.

According to a currently known technique, the female element comprises an internal hollow body with an end provided with fastening means to one of the pipes to be joined and to a hollow external body coaxial with said internal body and having an end which axially protrudes with respect to the other end of the internal body opposite to that provided with fastening means.

The internal body coaxially supports a rigid central stem having a widened end near said protruding end of the external body. With said widened end, a sealing bush axially sliding and coaxially arranged about said stem is elastically stressed to engage to prevent the passage of fluid within the female element.

An elastically stressed cleaning bush is coaxially arranged about the sealing bush to prevent the entrance of dirt about the sealing bush.

Finally, a sliding or turning sleeve is envisaged about the protruding end of the external body which is snappingly engageable or screwed with a complementary end of the male element to ensure the stable union of the two male and female elements of the fitting.

For supporting and fastening the stem to the internal body of the female element, a transversal base is provided in some known fittings with circumferentially arranged shaped holes axially and radially locked by mechanical stops made between the fastening nut and the corresponding end of the internal body. The stem is fixed to the base by means of a terminal thread which passes through the base and a lock nut placed on the opposite side of the base itself.

An example of a fitting of this type is described in EP-A-0 542 342.

In this fitting, the stem must withstand the hydraulic pressure possibly existing within the female element and the elastic action exerted by the sealing bush of the female element, as well as the elastic force exerted, with elements coupled, by the springs of the male element. It may thus occur in time that the threaded fastening of the stem to the base may slacken and the lock nut may slip off, entering into circulation in the hydraulic system to which the fitting belongs.

In view of this prior art, the object of the present invention is to make a female quick coupling fitting element for pipes envisaging a more precise, stable and safe positioning of the central stem.

According to the present invention, this object is reached by a female element comprising a hollow internal body having an end provided with fastening means to one of the pipes to be joined, a coaxial hollow external body with said internal body and having an end which axially protrudes with respect to another end of the internal body opposite to that provided with fastening means, one rigid central stem coaxially supported by said internal body by means of a transversal perforated base and having a widened end near said protruding end of said external body, an axially sliding sealing bush coaxially arranged about said stem and elastically stressed to engage with said widened end of the stem to prevent the passage of fluid within the female element, a cleaning bush coaxially arranged about the sealing bush and axially stressed in position so as to prevent the entrance of dirt about the sealing bush and a lock sleeve arranged about the protruding end of the external body and engageable with a complementary end of a male element to ensure the stable union of the two male and female elements of the fitting, characterised in that said stem is fixed to said base by means of at least one half bush radially and axially locked in corresponding seats of said stem and said base.

In the female element according to the invention, the central stem is therefore no longer fastened to the base by means of a threaded end and lock nut, but it is instead firmly locked with respect to it by means of one or more half bushes which in turn cannot move from the seats intended for them.

The lock nut can neither slacken or get lost, and at the same time assembly and disassembly is easier.

The features of the present invention will be made more apparent by the following detailed description of a non-limitative example of a female element shown in the accompanying drawings, in which:

FIG. 1 shows a female fitting element according to the present invention, partially in side view and partially in longitudinal section;

FIG. 2 shows a cross-section of said female element taken along line II in FIG. 1.

FIG. 1 shows a female pipe fitting element, which is indicated as a whole by number 1 and comprises a hollow internal body 2 made of two parts 3 and 4, the first of which ends with a threaded nut 5 suitable for fastening the female element 1 to one of the pipes to be joined.

On part 3 of the internal body 2 an end 6 of an external hollow body 7 is screwed, coaxial with said internal body, whose other end 8 axially protrudes with respect to part 4 of internal body 2.

Internal body 2 coaxially supports a rigid central stem 9 having a widened end 10 with seal 11 near said protruding end 8 from the external body 7.

A sealing bush 12 is coaxially arranged, in an axially sliding manner, about stem 9 and is stressed by a spring 13 to engage with seal 11 of widened end 10 of the stem itself to prevent the passage of fluid to or from within the female element 1.

A cleaning bush 14 under the bias of a spring 15 is coaxially arranged about sealing bush 12 to prevent the entrance of dirt about the sealing bush.

About end 8 of external body 7 a lock sleeve 16 is turningly and slidingly arranged, whose internal threading 17 is engageable with a corresponding external threading of the external body of a male element to lock the two elements together and to allow one an internal body of the male element to push the sealing bush 12 backwards and open communication between the internal passages of said male and female elements.

An example of such screw coupling is described and illustrated in EP-A-0 580 233.

The support and the fastening of stem 9 within internal body 2 is obtained by means of a transversal base 18 (FIG. 2) which is crossed by circumferentially arranged shaped holes 19 and axially and radially locked by a similarly perforated plate 20 and by mechanical stops 21, 22, 23 and 24 made in parts 3 and 4 of the internal body 2. Two half bushes 25 (FIG. 2) are interposed and locked with two facing concavities between the stem 9 and the base 18 within respective seats 26 e 27. Plate 20 prevents any movement of the two half bushes 25 and bottom 19, and consequently of step 9. 

1-3. (canceled)
 4. A female element (1) comprising a hollow internal body (2) having an end (3) provided with fastening means (5) to one of the pipes to be joined, a coaxial hollow external body (7) with said internal body (2) and having an end (8) which axially protrudes with respect to another end (4) of the internal body (2) opposite to that provided with fastening means (5), one rigid central stem (9) coaxially supported by said internal body (2) by means of a transversal perforated base (18) and having a widened end (10) near said protruding end (8) of said external body (7), an axially sliding sealing bush (12) coaxially arranged about said stem (9) and elastically stressed to be engaged with said widened end (10) of the stem (9) to prevent the passage of fluid within the female element (1), a cleaning bush (14) coaxially arranged about the sealing bush (12) and axially stressed in position so as to prevent the entrance of dirt about the sealing bush (12) and a lock sleeve (16) arranged about the protruding end (8) of the external body (7) and engageable with a complementary end of a male element to ensure the stable union of the two male and female elements of the fitting, wherein said stem (9) is fixed to said base (18) by means of at least one half bush (25) radially fitted and axially locked in corresponding seats (26, 27) of said stem (9) and said base (18).
 5. A female element according to claim 4, wherein it comprises a perforated plate (20) arranged between said base (18), said at least one half bush (25) and a mechanical stop of said internal body (2) to axially lock in position said base (18) and said at least one half bush (25).
 6. A female element according to claim 4, wherein at least one half bush (25) consists of two facing half bushes.
 7. A female element according to claim 5, wherein at least one half bush (25) consists of two facing half bushes. 